Insect repellent



Patented Jan. 8, 1952 INSECT REPELLENT Nathan L. Drake, College Heights, Md., and Charles, M. Eaker, Affton, Mo., assignors to the United States of America as represented by the Secretary of the Army No Drawing. Application January 11,1949,

Serial No. 70,394

9 Claims. (Cl. 167-30).

1 This invention relates to insect repellents. We have found that the application of 1,4-cyclohexanediol monopropionate, a compound having the structural formula H 01!!- moved under reduced pressure.

cooled until the diester crystallizes. The diester is collected on a cold filter and the filtrate saved. Hie cm The diester is put back into the flask and heated with 400 ml. water until the solid melts. Thev )0 mixture is cooled and the diester again removed. This is repeated at least once more. The aqueous H OH filtrate is extracted four times with a 200 ml. porto the human skin or to a fabric affords effective protection against insect bites, by repelling insects, particularly Aedes aeaypti and Anopheles minute intervals at 3 minutes each until the, first insect bite.

Tests to measure the repellency of 1,4-cyclohexanediol monopropionate, impregnated fabrics.

against Aedes ueczmti were conducted by uniformly impregnating mercerized cotton hose with the compound at. a rate equivalent to 3.3 gms. per sq. ft., drawing the dried hose over the arms of test personnel, who then thrust their covered arms into cages containing Aedes aegypti for 1 to 2 minutes. If no bites or'less than .5 bites, were received, the tests were repeated each successive day until 5 or more bites during one exposure were received.

It was found that the application of 1,4-cyclohexanediol monopropionate affords protection against Aedes aegypti for an average of 311 minutes. Against Anopheles quadrimaculatus, an average repellency time of 46 minutes was noted in analogous tests.

It was found that fabric impregnated with 1,4-cyc1ohexanediol monopropionate remained repellent for over successive days.

Surprisingly, it was found that the corresponding diester, 1,4-cyclohexanedlol dipropionate. lacks insect repellency if applied to the skin, and upon application to a fabric repels insects for only a fraction of the time for which the monoester protects.

1,4-cyclohexanediol monopropionate may be against,

made, for instance, by conversion of the corresponding diester, as follows:

dissolved in 1050 ml. of 50% ethanol at 40-50, 33 gms. of potassium hydroxide in 150 cc. of 5% ethanol are added. The mixture is shaken vigorously for 5 minutes and then the alcohol is re- The residue is tion of chloroform. The chloroform is dried over MgSO4, filtered and distilled. The monoester distills at -92/0.5 mm. The yield is 48 g., 37% of theory; its refractive index is n =1.4(515.

For ease of application to the skin, the 1,4-cyclohexanediol monopropionate. may be incorporated in a suitable inert liquid or solid carrier such as mineral oil, alcohol, petrolatum, etc. For

ease and uniformity of application to the fabric, the 1,4-cyclohexanediol monopropionate may be applied to the fabric in an inert solvent, such as alcohol, ether, etc.

Having thus described our invention, we claim:

1. An insect-repellent fabric comprising fabric impregnated with 1,4-cyclohexanediol monopropionate.

2. An insect repellent composition comprising 1,4-cyclohexanediol monopropionate in a nongaseous inert organic carrier.

3. An insect repellent composition containingas an essential active ingredient 1,4-cyclohexanediol monopropionate, and a non-toxic insectrepellent-adjuvant as a carrier therefor.

4. An insect-repellent composition comprising 1,4-cyclohexanediol monopropionate in alcohol.

5. An insect-repellent composition comprising 1,4-cyelohexanediol monopropionate in ether.

6. An insect-repellent composition comprising 1,4-cyc1ohexanediol monopropionate in oil.

7. An insect-repellent composition comprising 1,4-cyclohexanediol monopropionate in petrolatum.

8. A process of repelling insects comprising applying 1,4-cyclohexanediol monopropionate to theregion from which the insects are to be. repelled.

9. A process of repelling insects comprising applying l,4-cyclohexanediol monopropionate to the skin.

NATHAN L. DRAKE. CHARLES -M. EAKER.

g. lA-cyclohexanediol .diproprionate: are. 66 (References. on following page) REFERENCES CITED OTHER REFERENCES The following references are of record in the 0. S. R, D., Insect Control Committee Report file of this patent: No. 28, Interim Report No. 0-94, page 39, May 18,

1945. T PTENTB 5 Palfrey; q m rend 1s9,v18 :1s9 (1929). Number I "Name t 'Aldersleyg Cliem fsqenf pqndon, 1940,

2,400,006" Jones et a1 May '1, 1946 D1mroth: Berichte 753, 317-321 (1942). 

2. AN INSECT REPELLENT COMPOSITION COMPRISING 1,4-CYCLOHEXANEDIOL MONOPROPIONATE IN A NONGASEOUS INERT ORGANIC CARRIER. 